In the past, there have been known discharge lamp lighting devices for lighting discharge lamps (see Document 1 [JP 2013-251187 A]).
The discharge lamp lighting devices disclosed in Document 1 determine that an electrical fault has occurred, when a state in which a difference between a measured voltage value of one polarity and a measured voltage value of the other polarity is equal to or greater than a threshold value continues for a predetermined time period. Accordingly, even if a ground fault (earth fault) occurs with a high ground fault resistance, the discharge lamp lighting devices can detect such a ground fault.
It is demanded that lighting devices such as the discharge lamp lighting devices disclosed in Document 1 detect a ground fault more successfully.